In the dental industry, light curing devices serve to polymerize polymerizable dental restorations. For this purpose, the device is provided with a light source whose light emission is attuned to the dental restoration material to be cured. As dental restorations have to be mounted at most various places in the upper jaw and lower jaw in the mouth of a patient easy handling and application of the light curing device in various positions relative to the mouth of the patient are indispensable.
In order to guarantee an ergonomic handling such light curing devices have substantially the shape of a pistol or of a rod. Besides the light source, the housing of the light curing device must also receive energy sources such as accumulators, and the control electronics for the realization of the polymerization cycle.
The basic design of such a light curing device is disclosed in DE 10 2006 035 658 A1 and corresponding U.S. Pat. No. 8,113,831 (B2), which is hereby incorporated by reference. The light curing device described is provided with an actuation switch at its bottom side with a pushbutton function, and at its top side which is facing the operator, a display device.
Such display devices are important in order to give the operator quickly discoverable and brief information on the exposure state but also, for example, to inform the operator if the available residual capacity of the energy storage unit is sufficient for the desired polymerization cycle.
While the release button of the disclosure mentioned can practically only be pressed with the index finger of the operator, or possibly with his or her middle finger, today especially young dentists wish to operate the release button with their thumb. This means that it is appropriate that the button concerned is attached closer to the top of the dental light curing device, as is the case with rod-shaped light curing devices anyway.
While a button, which is mounted to the bottom side of the light curing device in the manner of the trigger of a pistol, is actuated almost automatically due to the natural way of holding the device, with a button on the top this is only the case when the operator aims at the button with his or her finger in a targeted manner. In this connection, it must be taken into consideration that the dentist directs his attention primarily not to the device but to the mouth of the patient and the dental restoration which is located there and needs to position the light exiting end of the light curing device precisely at the right spot and to hold the device continuously, at least during the light curing.
In order to still make possible a reliable release of the button, it has been suggested to enlarge the size of the release button.
Surprisingly enough, the operability is even worse with a larger release button so that the producers of light curing devices almost exclusively use a release button whose size is not larger than the size of a human finger tip, for example, a diameter of less than 8 mm.